Foraminiferal taphofacies in the Mississippian rocks of the Guadiato area, SW Spain

Abstract

Microfacies analysis of over 1800 standard thin-sections of upper Visean and Pendleian-aged platform limestones from southwestern Spain (Guadiato area) shows that foraminiferal assemblages contain many allochthonous specimens. The analysis of the cementation, recrystallization, abrasion, bioerosion, encrustation, dissolution, taphonomic distortion, orientation and sorting allow the recognition of eight taphofacies. They are based on the taphonomic features observed within the foraminiferal assemblages, which reflect the environmental conditions in which foraminifera were sedimented as well as about early diagenesis. The environmental conditions may be ascertained from the analysis of the biostratinomic processes, which comprise the energy, waves, tides, redox conditions, etc. The mechanisms of taphonomic alteration may be quantified, and thus the appearance or absence of these alterations may be used to define taphofacies of shallow- and deep-water environments, such as those from tidal flat, shoal, outer platform, microbial mound or slope. Moreover, the relationship among these taphofacies also helps to define depositional mechanisms and products, such as debris flows or olistolites.